ESBL ecoli uti recurring

Hi everyone,
I am new here and hopeful you all can give me some ideas. I have had recrring esbls all ecoli uti's for the last 6 months. I have been thru 2 infectious d. drs, and a urologist. My newest ID has said she is stumped and does not know what else to do. I am awaiting an appt at the university with their urology dept.
I have always had utis so i am resistant to everything oral now. I did 6 weeks iv of invanz fom may thru july. esbl back in 10 days, since then, have done Fosofomycin for 30 day(10 doses) , 10 days after , tests show its back but mild. Help dont know what else to try, did eveything from 3000 vit c, and cranberry to d-mannose.
For some reason why is it, that if i take say bactim, it eases symptoms, even though its resistant to it. Also tried 30 days bactrim to see if that might do it, and that was a no.
I ve had most everytest done, cystoscopy thru gallium studies. all inconclusive. I really dont know where else to turn, is this colonization, since my symptoms come and go? My gi tract is also in disarray, and my immune system is in the toliet according to the last labs. Also show high allergy numbers according to ID, DR. Where do i turn next?